Wifi Smart Thermostat with ESP32 and Android

Android app to build a thermostat and control your home heating with an old Android device, a couple of ESP32, a relay and a DHT sensor.

IntermediateWork in progress2 hours24,230

Wifi Smart Thermostat with ESP32 and Android

Things used in this project

Hardware components

ControlEverything.com High-Power Relay Shield for Particle Photon I²C 1-Channel SPDT 10-Amp

It is very important to use a High Level Triggered Relay for this project.

Espressif ESP32S

In the Pi version you can connect the relay and the sensor directly. Despite of that, or if you are using the "Old Relic" version, you can have remote nodes based on ESP32 microcontrollers, to measure the temperature in other rooms of your house.

DHT22 Temperature Sensor

For the remote nodes based on ESP32 microcontrollers, the DHT11 or DHT22 sensors are used. We recommend the DHT22 because it is more reliable and accurate than the DH11.

Software apps and online services

Wifi Smart Thermostat Android app

You can install this app on an old Android device (4.1+), and with help of a couple of ESP32, a relay and a DHTtemperature sensor, let it control your home heating.

Story

This project is the continuation of an Thermostat developed for the Arduino Yun microcontroller in year 2013.

Even though this old project works, I was not happy with the costs (the Yun is expensive compared to an ESP32) and the difficulty to make the Yun made the things that I wanted.

Because of that, and taking advantage of the new ESP32 mcu's, I developed an Android app to give the users the chance to build a Smart Thermostat as cheap as possible.

The Wifi Smart Thermostat app

The WIfi Smart Thermostat app is an Android App that works in devices with Android 4.1+. The typical devices that you have forgotten in a drawer, because they are old, and you don't use them anymore.

With this app, an ESP32 microcontroller, a DHT temperature / humidity sensor and a High Level Triggered relay, you can build a Smart Thermostat to control the boiler of your home heating system.

Here you have the Smart Thermostat "Old Relic" app working on an old Nexus 7 (2012)

In the picture above you can see the Wifi Smart Thermostat app working on an old Nexus 7 (2012). The app is using five nodes based on ESP32 microcontrollers: four of them measuring the temperature and humidity in several rooms of the house. The other one has a high level relay attached to it and is connected to the boiler.

The app is acting as thermostat, deciding when to heat of cold down depending on the configured settings.

Here you have an ESP32 and a DHT11, acting as "remote temperature/humidity node".

And here an ESP32 with a High Level relay. This relay is connected to the boiler.

You can connect the temperature sensor and the relay to the same ESP32 too.

Of course you can install the same app on another device and configure it as "client". Then you will be able to control your thermostat remotely, when you are not at home. A thermostat can have as many client as you want.

Smart Thermostat Client

The use of the app is free (supported with ads, and optionaly you can buy credits to disable the ads and support the project).

If you find this project interesting, please visit us on our web site: www.smart-thermostat.eu

All kind of comments and suggestions are welcome!